玉米乙醇工艺中纤维素的降解转化研究
毕业论文关键词 燃料乙醇 玉米发酵 纤文素酶
Title Study of cellulose conversion during corn ethanol process
Abstract Fuel ethanol is produced from biological materials through fermentation and other means, and is used as a fuel. Fuel ethanol can be used as liquid fuel and gasoline additive, which is renewable energy and plays an important role in alleviating the energy crisis and protecting the environment. At present, the application of corn fermentation technology is widely used in the production of ethanol. However, the cellulose, which accounts for 4% of the corn mass, is not converted in traditional corn ethanol process. This work studied the effect of cellulase addition in corn ethanol process. The factors such as cellulase cocktail source, cellulase dosage, the time for cellulase addition and process pH were examined. We also studied the effect of cellulase addition at different solids loadings as well as the effect of hemicellulase addition. Adding cellulase increased the yield of ethanol and the cellulase cocktail obtained from Heshibi showed the best effect among the tested cellulase cocktails. Cellulase dosage at 0.6% (dry corn basis) enhanced ethanol yield the most. Addition of cellulase during simultaneous saccharification and fermentation was the best process for ethanol enhancement. Addition of cellulase at 33% solids loading increased ethanol yield more than that at 27% solids loading. Kinetic study showed that 87.22% of ethanol was produced during the first 24 h. After optimization, the final ethanol concentration reached as high as 138 g/L, which is 3.4% higher than traditional process without addition of cellulase.
Keywords fuel ethanol corn fermentation cellulase
目次
1引言1
1.1燃料乙醇的研究意义.1
1.2燃料乙醇的国内外发展状况.1
1.3燃料乙醇的生产工艺.2
1.3.1第一代燃料乙醇：玉米燃料乙醇生产工艺.2
1.3.2第二代燃料乙醇.3
1.4纤文素酶.3
1.4.1纤文素酶组成和作用机制.3
1.4.2纤文素酶水解的影响因素.4
1.5本课题的目的.5
2材料与方法6
2.1实验器材.6
2.2实验试剂.6
2.3实验方法.7
2.3.1基本实验步骤.7
2.3.2灭菌条件.7
2.3.3乙醇、木糖、甘油含量测定.7
3实验结果与讨论8
3.1不同厂家的纤文素酶对发酵的影响.8
3.2尤特尔纤文素酶对乙醇产量的影响.9
3.3添加工艺的影响10
3.4不同干物浓度下添加不同量的纤文素酶11
3.5发酵初始pH对发酵的影响.12
3.6纤文素酶与半纤文素酶一同添加的影响13